Tumor threats the human health seriously. There are about 200 million cancer patients in China and the number is added by 1.6 million per year, which is a big group. The anti-cancer research is a challenging and significant field in life science and technology. At present, the commonly used clinical anti-cancer drugs are cytotoxic drugs. The characteristics of these drugs are poor selectivity, strong side effects, drug resistance and so on. They are a typical double-edged sword drugs, and difficult to eradicate cancer, which result in high proportion of cancer recurrence. The high rate of the recurrence of cancer has troubled the doctors, and more and more studies confirm that there are a few tumor stem cells in the tumor cell population which can amplify the cell groups. Tumor stem cells are usually in a slow cycle status and have low sensitivity to chemotherapeutic drugs. They are the source of tumor recurrence. The found of the tumor stem cell makes a new target for cancer treatment, and the drug research focused on the tumor stem cell may be able to cure cancer completely.
In recent years, investigations on anti-cancer compounds from natural products have become the hotspot of anti-cancer drug development. For the past 20 years, 61% new small molecule entities drugs may be derived from natural products. Natural products are very common in some therapeutic areas: 78% of the antibacterial compounds and 74% of anti-tumor compounds are natural products or derived from natural products. Practice has proved that the unique role of natural products in anticancer drug discovery re-attach great attention. The traditional treatment of cancer chemotherapy drug have resistance problem, especially the low sensitivity to tumor stem cells. Traditional Chinese medicine (TCM) is profound in anti-cancer field, high efficiency and low toxicity. Accordingly, there is high chance to find drugs eradicating cancer stem cells for cure of malignant tumor from TCM.
Parthenolide, a sesquiterpene lactone extracted from Tanacetum Parthenium, was originally used to treat skin infections, rheumatism, and migraine. Recent studies have shown that parthenolide can inhibit the growth of cancer cells, such as prostate cancer, breast cancer, gastric cancer, leukemia, kidney cancer, lung cancer, colon adenocarcinoma, and medulloblastoma. Furthermore, parthenolide is effective on treatment of UV-induced skin cancer in animal model. The study of its mechanism finds that parthenolide can inhibit the activation of the transcription factor NF-κB. The activity was mainly derived from the thiol on the subunit of p65/NF-κB which conducts Michael addition reaction with parthenolide. NF-κB is a key gene to regulate tumor invasion, metastasis, and drug resistance genes; therefore, inhibition of NF-κB activation may increase the sensitivity of tumor apoptosis to tumor inhibitor. Recently, Ph.D. Jordan, C. T. and his colleagues found that parthenolide can selectively eliminate cancer stem cells without damage of normal stem cells, which make it possible to suppress recurrence AML. This unique mechanism action of parthenolide has attracted widespread attention.
Micheliolide belongs to guaiane-type sesquiterpene lacones. It has been reported in the literature [J. Nat. Prod. 1993, 56, 90-98; Bioorg. Med. Chem. Lett. 2003, 11, 1503-1510]. On the basis of the results, the present invention reports the use of micheliolide derivatives and its salts in the cancer treatment.